Processes which separate air via cryogenic distillation require a heat exchanger system in order to make the process workable and/or to achieve a power savings. The conventional heat exchanger system employs separate heat exchangers for each type of heat exchange service. For example, the heat exchanger system will at the very least include (1) a main or primary heat exchanger for cooling the feed air to a temperature near its dew point against other warming process streams and (2) a reboiler/condenser for condensing a nitrogen-rich gaseous overhead stream against a vaporizing oxygen-enriched liquid bottoms stream. The heat exchanger system will often further comprise a subcooler for subcooling a liquid process stream to a temperature lower than its bubble point.
The problems with the conventional heat exchanger system include the high cost of purchasing separate heat exchangers as well as the pressure drop and costs associated with the piping connecting the heat exchangers. It is an object of the present invention to minimize these problems associated with the conventional heat exchanger system.